Non equilibrium anisotropic excitons in atomically thin ReS${}_2$

Abstract

We present a systematic investigation of the electronic properties of bulk and few layer ReS${}_2$ van der Waals crystals using low temperature optical spectroscopy. Weak photoluminescence emission is observed from two non-degenerate band edge excitonic transitions separated by $\sim$ 20 meV. The comparable emission intensity of both excitonic transitions is incompatible with a fully thermalized (Boltzmann) distribution of excitons, indicating the hot nature of the emission. While DFT calculations predict bilayer ReS${}_2$ to have a direct fundamental band gap, our optical data suggests that the fundamental gap is indirect in all cases.

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Cited by in corpus (4)

• Additional excitonic features and momentum-dark states in ReS2
• Dimensionality and Anisotropicity Dependence of Radiative Recombination in Nanostructured Phosphorene
• Inlaid ReS2 Quantum Dots in Monolayer MoS2
• Exchange-split multiple Rydberg series of excitons in anisotropic quasi two-dimensional ReS${}_2$